package com.pang.springcloud.lib;

import org.springframework.cloud.client.ServiceInstance;
import org.springframework.stereotype.Component;

import java.util.List;
import java.util.concurrent.atomic.AtomicInteger;

/**
 * @author： pang-yun
 * @date： 2022-02-10 13:42
 * Description:
 */

@Component
public class MyLoadBalancer implements LoadBalancer {
    private AtomicInteger atomicInteger = new AtomicInteger(0);

    public final int getAndIncrement() {
        int current;
        int next;

        do {
            current = atomicInteger.get();
            next = current >= Integer.MAX_VALUE ? 0 : current + 1;
        } while (!atomicInteger.compareAndSet(current, next));

        System.out.println("-------第几次访问: " + next);
        return next;
    }

    // 负载均衡算法， rest接口第几次请求数 % 服务器集群总数量 = 实际调用服务器位置下标， 每次服务重启后rest接口计数从1 开始
    @Override
    public ServiceInstance instances(List<ServiceInstance> serviceInstances) {
        int index = getAndIncrement() % serviceInstances.size();
        return serviceInstances.get(index);
    }
}
